Auxiliary fittings, 3‑way switch for HIC HZI300

What is HZI300?

It is an additional auxiliary contact block designed for mounting on overload switches of the HIC series. It has three independent switching contacts (1NO + 1NC + 1NO), which allow signalling the device status – e.g., whether the switch is on or has tripped due to overload. It is mounted laterally, without opening the circuit – just slide it onto the busbar and lock it.

Who is it for and what is it used for?

For the installer it is a simple way to add control or signalling functions without replacing the whole switch. Just add the HZI300 to an existing HIC – and you get access to three contacts that can be wired to a controller, indicator, or even a BMS system. For the end user it means greater transparency – e.g., you instantly know whether the installation is operating or has shut down due to a fault, without having to check the panel.

How does it work?

The contacts are screw‑connected – no special terminals or tools are required. The maximum operating current is 5 A at 230 V AC (AC-15), which is sufficient for signalling circuits, relay coils or small control devices. It is not intended for carrying large currents – it is an auxiliary, not a power, contact. Its purpose: to indicate what is happening in the main circuit.

What it does not do?

It does not increase the switch’s breaking capacity. It does not provide short‑circuit protection. It has no diverter contacts or fault signalling – only pure switching. It does not operate at DC voltages above 30 V (although the data sheet does not specify a DC value, remember the limit of 5 A at 30 V DC as stated by the manufacturer). It is not mounted from the top – only laterally on a DIN rail.

Why use it?

Because it allows rapid expansion of the functionality of an existing system. Instead of replacing the whole switch with a model that has built‑in signalling, you simply add this block. Installation takes seconds. No change to the control program is required – just connect wires to the new contacts. It complies with standards for modular devices – there are no “secret” parameters.